Field of the Invention
The present invention relates to wireless communication and, more particularly, to a packet-transmission method performed by a node in a wireless communication system and a user equipment (UE) using the method.
Related Art
In the International Telecommunication Union Radio Communication Sector (ITU-R), standardization of International Mobile Telecommunication (IMT)-Advanced, a next generation mobile communication system after 3rd generation, is underway. IMT-Advanced aims to support IP (Internet Protocol) based multimedia service at data rates of 1 Gbps in a stationary and low-speed moving state and 100 Mbps in a high-speed moving state.
The 3rd Generation Partnership Project (3GPP) is a system standard that meets the requirements of IMT-Advanced, and LTE-Advanced (LTE-A), which has improved Long Term Evolution (LTE) based on Orthogonal Frequency Division Multiple Access (OFDMA)/Single Carrier-LTE-Advanced (LTE-A), is being prepared. LTE-A is one of the strong candidates for IMT-Advanced.
Recently, there has been a growing interest in D2D (Device-to-Device) technology for direct communication between devices. In particular, D2D is attracting attention as a communication technology for the public safety network. Commercial communication networks are rapidly changing to LTE, but current public safety networks are mainly based on 2G technology in terms of conflicts with existing communication standards and cost. These technological gaps and demands for improved services have led to efforts to improve public safety networks.
Public safety networks have higher service requirements (reliability and security) than commercial communication networks and require direct signal transmission and reception, or D2D operation, between devices, especially when the coverage of cellular communications is insufficient or unavailable.
For example, D2D operation in general can have a variety of advantages in that it transmits and receives signals between nearby devices. For example, the D2D UE has high data rate and low delay and is capable of data communication. Also, the D2D operation can disperse the traffic to the base station, and can also expand the coverage of the base station if the UE performing the D2D operation acts as a repeater. Communication related to a vehicle, including transmission and reception of signals between vehicles with the above-mentioned extension of D2D communication, is called V2X (VEHICLE-TO-X) communication in particular.
On a multi-hop wireless access network architecture, when a UE transmits a packet using D2D communication, it is important to determine the route through which the packet will be efficiently transmitted. However, according to the prior art, when a packet is transmitted, a problem occurs that it takes a comparatively long time to determine the route to which the packet is to be transmitted.
Accordingly, the present invention provides a method for efficiently determining a route for transmitting a packet on a multi-hop wireless access network and transmitting an uplink packet or a downlink packet based on the determined route.